RMGA Pipeline Installation 4 — Questions and Answers
Question 1: During initial pressure testing of a new medical gas pipeline system, what gas must be used for the standing pressure test?
- Oxygen
- Medical air
- Oil-free dry nitrogen (Correct answer)
- Carbon dioxide
Correct answer: Oil-free dry nitrogen
Oil-free dry nitrogen must be used for pressure testing medical gas pipelines to avoid introducing combustion risk, moisture, or contamination.
Question 2: What is the required initial pressure for the high-pressure standing test on a new medical gas distribution system per NFPA 99?
- 50 psi
- 100 psi
- 150 psi (Correct answer)
- 200 psi
Correct answer: 150 psi
The high-pressure standing test requires the system to hold 150 psi with nitrogen for a defined period without measurable pressure loss.
Question 3: Cross-connection testing between different medical gas systems is required to verify which condition?
- That each outlet delivers the correct gas identity (Correct answer)
- That pressure is uniform across all outlets
- That flow rates meet peak demand
- That alarm systems activate at correct setpoints
Correct answer: That each outlet delivers the correct gas identity
Cross-connection testing confirms that each outlet is connected to the correct gas source and no mixing of gas species has occurred during installation.
Question 4: Medical gas piping must be labeled at maximum intervals of how many feet in accessible spaces per NFPA 99?
- 10 feet
- 20 feet (Correct answer)
- 50 feet
- 100 feet
Correct answer: 20 feet
NFPA 99 requires medical gas piping to be labeled with the gas name and direction of flow at intervals not exceeding 20 feet in accessible areas.
Question 5: Which of the following is the correct method for joining copper tubing sections in a medical gas pipeline?
- Silver solder using 50/50 tin-lead solder
- Brazing with BCuP-5 filler metal using no flux
- Brazing with BAg-series filler metal and appropriate flux (Correct answer)
- Compression fittings rated for gas service
Correct answer: Brazing with BAg-series filler metal and appropriate flux
Medical gas copper piping is joined by brazing using BAg (silver-based) alloys with compatible flux, which produces joints rated for high-purity gas service.
Question 6: When installing a pressure/vacuum indicator alarm system, where must alarm panels for patient care areas be located?
- Only at the source equipment room
- At the nurses' station or other continuously monitored location (Correct answer)
- Inside each patient room
- At each zone valve box
Correct answer: At the nurses' station or other continuously monitored location
Area alarm panels must be located at continuously staffed locations such as nurses' stations so that pressure or vacuum failures are detected immediately.
Question 7: Medical gas outlet stations in patient care areas must be designed so that adapters for different gases are:
- Color-coded only, with a universal connection
- Non-interchangeable and gas-specific (DISS or PISS connections) (Correct answer)
- Threaded and labeled with the gas name
- Interchangeable but locked with a keyed system
Correct answer: Non-interchangeable and gas-specific (DISS or PISS connections)
Outlet stations use DISS (Diameter Index Safety System) or PISS connections that are gas-specific and physically non-interchangeable to prevent wrong-gas connections.
RMGA Pipeline Installation 4
During initial pressure testing of a new medical gas pipeline system, what gas must be used for the standing pressure test?